Before using pgrouting, I have to create the node ids. I loaded my polyline layer into PostGIS Manager：
I type this in SQL query：
select assign_vertex_id('split_4', 800, 'geom', 'gid')
But as I click the "Execute" button, I got this error：
Error: Function StartPoint (geometry) does not exist LINE 1: SELECT gid AS id, StartPoint (geom) AS source, EndPoint (geom) ... ^ HINT: did not comply with the specified name and parameter types of function. You may need to add explicit type conversion. QUERY: SELECT gid AS id, StartPoint (geom) AS source, EndPoint (geom) as target FROM split_4 CONTEXT: PL / pgSQL function "assign_vertex_id" line 23 at target EXECUTE statement FOR
I searched for ST_StartPoint, and found that it needs working with linestring, so I cut my multilinestring to a linestring(named it "ways"), and then run the SQL：
ALTER TABLE ways ADD COLUMN source integer; ALTER TABLE ways ADD COLUMN target integer; SELECT assign_vertex_id('ways', 800, 'the_geom', 'gid');
but got the same error above.
How to solve this and to create the node ids, then I can proceed to the next step in A Beginner’s Guide to pgRouting？I'm working with pgadmin3, postgresql8.4, PostGIS2.0 under WIN7-64bits.